This invention relates generally to a thin type display device with a matrix array of pixels and, more particularly, a thin type display panel including a display section having a built-in active matrix using thin film transistors (TFTs) and a display drive circuit section.
Recently, a growing demand has been made for a thin type display device, such as an electroluminescent (EL) panel, plasma display device and liquid crystal (LC) display device, to be used as a display device for terminal units of a measuring apparatus, business machine and computer in place of a conventional cathode ray tube (CRT). Greater attention has been paid to liquid crystal (LC) display devices in view of their low dissipation power and cost.
According to the LC display device, switching elements, such as thin film transistors, are formed in a matrix array in the display area of a substrate to provide an active matrix. The image data is stored for a predetermined time for each point (pixel) of the switching transistor matrix and a pixel (or cell) area of the liquid crystal layer is correspondingly oriented according to the stored image data. In this way, a desired image is displayed on a display area. The LC display device with a switching transistor matrix array performs a full-time image display and assures a high-quality reproduction image. The thin film transistor of the LC display device can relatively easily be formed on a glass substrate, using the thin film technique for a polycrystalline semiconductor and amorphous semiconductor. It is, therefore, considered that it is possible to implement a thin type display panel of a larger area as required.
In actual practice, however, it is difficult to achieve a liquid crystal display panel of a larger display area with a better cost performance. If the active matrix size (panel size) of the LC display device is increased, the electric display device operation becomes complex by that extent and thus the peripheral drive circuit configuration also becomes complex. In a conventional LC display device with a switching transistor matrix array, the display drive circuit is formed with a plurality of IC chips, such as IC memories, IC data selectors and IC decoders, arranged on a special printed circuit board other than a display substrate. The display drive circuit is connected by a wire bonding method to the display substrate. If, with the greater complexity of the drive circuit configuration, the interconnection pattern of the circuit board and bonding pad pattern are microminiaturized as appreciated from, for example, a pattern pitch of about 100 to 150 .mu.m, it would be difficult to manufacture the display drive substrate, as well as to perform a wire bonding connection treatment. This leads to a low manufacturing yield of the LC display device. Furthermore, with an increase in the display area of the panel, a selective drive operation is delayed at the active matrix and a response speed (display operation) at the panel is delayed by that extent.